Many of the component parts, such as the electric generator, frequency converter, etc., of a wind power turbine for producing electric energy generate heat that must somehow be dissipated.
In some wind turbines, certain components are cooled by a coolant circuit, as described, for example, in U.S. Pat. No. 6,520,737.
Fluid cooling, however, calls for careful maintenance of the circuit and provision of a coolant tank.
Alternatively, as described, for example, in EP Patent Application No. 1,200,733 or in PCT Patent Application No. WO 01/06121 A1, cooling is performed by a closed-loop circuit formed partly by the pylon itself, and in which an air stream is conveyed.
Alternatively, as described in PCT Patent Application No. WO 2007/110719, heat-producing component parts are cooled by fixing them directly to the wall of the pylon, relying on wind action on the pylon to cool them sufficiently.
PCT Patent Application No. WO 99/30031 discloses a cooling system for wind power turbine wherein the pylon itself defines the conduit and the chimney effect of the same is used to convey an air stream from the base to the top of the pylon and to cool those heat producing devices housed inside the pylon.
In the latter solutions, the pylon and more specifically, the outer wall of the pylon is the main heat exchange element. Even in exceptionally windy locations, however, wind action on the pylon is not always sufficient to adequately cool, directly or indirectly, component parts subject to overheating. That is, in weather conditions characterized by strong sunlight heating the pylon wall, and by relatively mild wind, the pylon fails to ensure adequate cooling of the converter.
In accordance to the arrangement disclosed in PCT Patent Application No. WO 2007/110719 and PCT Patent Application No. WO 99/30031, humid and dirty air is permitted to enter into the inner compartment where sophisticated electronic components are housed.
German Patent Application No. DE 199 47 915 A1 discloses a wind power turbine comprising a pylon having a first outer wall; a nacelle having a second outer wall; an electric generator fitted to the nacelle to produce electric energy; a heat generating apparatus housed in an apparatus space arranged at the base of the pylon; and a cooling system for cooling the heat generating apparatus. The cooling system is of the open-loop circuit type and includes a conduit, which is housed inside the pylon and the nacelle and connects an inlet port, formed in the apparatus space, to an outlet port formed in the nacelle.
The cooling conduit extends across the heat generating device and therefore introduces humid and dirty air into the heat generating device. Since the heat generating devices are often electronic power devices, such a cooling system may cause severe drawbacks to the operativeness of the wind power turbine.
Thus, it should be appreciated from the above that, in general, known cooling techniques are invariably far from satisfactory.